What is the ruling on implementing a deceased person's will that some heirs do not acknowledge, and what are the methods for proving it in the Hanbali and Shafi'i schools of thought?

The heirs are not obliged to execute the deceased's will unless it is proven by evidence, and the burden of proof is on the claimant, while the oath is on the defendant. A will is proven by testimony or writing, and writing accompanied by testimony constitutes the strongest evidence. As for writing alone, there is a difference of opinion among scholars regarding the validity of a will proven solely by it. The Hanbali school of thought holds that it is proven by it if the testator's handwriting is recognized. The Shafi'i school of thought holds that it is not proven by it unless it has been witnessed. If all adult and competent heirs acknowledge it, the will is established; otherwise, the case is brought before the judiciary.